Muscarinic receptors mediate the cellular actions of acetylcholine at the parasympathetic neuroeffector junction. In addition, these receptors mediate cholinergically mediated effects in the central nervous system (CNS), particularly in cortical and subcortical regions of the brain. Five muscarinic genes, m1 to m5 have been cloned, where m1, m2 and m3 appear to correspond to the pharmacological subtypes M1, M2 and M3 respectively. Muscarinic M3 antagonist are potentially useful as spasmolytics for the treatment of patients with various conditions involving smooth muscle spasms such as gastrointestinal motility disorders, functional diarrhea, irritable bowel syndrome, gastric and duodenal ulcers, spasms of the urinary tract and urinary incontinence. Scientists at Pfizer, Inc. have designed and synthesized Darifenacin for the treatment of urinary incontinence and irritable bowel disease. Tritium-labelled Darifenacin with high specific activity is required for receptor binding studies. The tritiated precursor from this labelling project will be converted to Darifenacin, which is a standard used to investigate the muscarinic receptor antagonist pharmacology. User Details: Experiment Details: User Number: 1616 Tritiation City, State: Palo Alto, CA NMR Funding Source: Industry Tritides Charge: $1752.52 1 day Program Income: $1505.70 1 compound